The genetic discipline cannot be uncoupled from bio-statistics, the tools to handle and analyze the large amount of data that are obtained from DNA, RNA and protein projects. The mathematics and bio-statistics give the genetic researcher the possibility to understand the genetic data, to interpret and to obtain maximum results from minimum data. The human race is characterized by variability, by polymorphisms. A polymorphism is a mendelian character which is present in at least two phenotypes in population, from which none is rare (i.e. none appears with a frequency lower then 1% – 2%). At the beginning the protein polymorphisms were used in population genetic studies, but there relatively low variability and the need of large amounts of biologic material made them hard to use in large scale genetic analysis. In 1978 the first DNA polymorphism was discovered (the B – globin gene). After that a cascade of types of DNA markers came, RFLP (Restriction Fragment Length Polymorphism), VNTR (Variable Number Tandem Repeats) and STR (Short Tandem Repeats), and the analysis of the genetic structure of human populations became easy, the challenging part for a biologist being now the interpretation, the formulation of an equation in which all the data to be present This was possible by creating a mathematical model, a representation of the biological processes, in which both observed laboratory data and expected data are described in quantitative way.
In this paper, the authors present a large picture of how mathematics and statistic help a researcher to give a meaning of his genetic observation. We used the polymorphism of two proteins (Haptoglobin and Transferrin) and two STR – DNA markers to make a population survey and to compare the genetic structure of Romanian population with other European and non-European population. The data were interpreted in statistical method, under Hardy-Weinberg condition, using X tests. Also, using several other STR DNA markers and math methods we exemplify bow linkage analysis can be a powerful tool for prenatal diagnostic of different genetic disorders and for finding new genes.